31896 - Harris Sil-Fos 15 Silver Brazing Alloy 3/32" - 1lb Tube

The HVAC Technician's Choice for Reliable Brazing

When you are up on a roof repairing an AC unit or installing a new refrigeration line set, you need a brazing rod that you can trust to hold up against vibration and temperature swings. Harris Sil-Fos 15 is the legendary 15% silver brazing alloy that professionals rely on for the most demanding copper joining tasks. Known simply as "15" in the trade, this rod is superior to standard 5% or 0% silver rods because the high silver content provides exceptional ductility. This means the joints you create are less brittle and can flex slightly with the expansion and contraction of pipes, preventing leaks in the long run.

Sil-Fos 15 is famous for its "sluggish" flow characteristics compared to more liquid alloys. This is a huge benefit when you are working with loose connections or vertical joints where you need the filler metal to stay put and build up a fillet. It fills gaps better than almost any other phos-copper rod. For copper-to-copper connections, you don't even need to carry a pot of flux—the rod fluxes itself as you heat it, saving you time and money. It flows smoothly at around 1475°F, wetting out the copper surface for a strong, leak-proof seal.

This 1 lb tube of 3/32" rods is the perfect size for your truck stock. The 3/32" diameter is versatile enough for both small capillary tubes and larger suction lines. Whether you are working on medical gas lines, heat exchangers, or standard air conditioning coils, Sil-Fos 15 gives you the confidence that your welds will pass inspection and stand the test of time. Note: If you are brazing brass valves or fittings to copper, remember to grab some Stay-Silv flux, as the self-fluxing magic only works on pure copper.

Why Choose Sil-Fos 15?

• Gap Filling: Best-in-class ability to bridge gaps in loose fit-ups.
• Vibration Resistance: High ductility prevents cracking in compressor lines.
• No Flux Needed: Self-fluxing on copper saves prep time.
• Corrosion Resistant: Stands up to harsh environments inside and outside the system.
• Versatile: Works on copper, brass, and bronze (flux required for brass/bronze).